Antibodies and B cells

PRRs

general binding when something is wrong, binds PAMPs and DAMPs, same receptors found in most humans, used for innate immunity, many cells produce but immune cells produce the most

AgRs

allow for a very specific response to be generated, bind epitopes, creates immune memory, different between humans, used in adaptive immunity, made randomly in advance of any infection

secondary lymphoid tissue

where T and B cells go after formation

clonal selection and expansion

factors of the adaptive immune system that allow the response to be specific and effective

surface bound (BCR) and secreted (Abs)

two types of antibodies

variable

this part of the antibody binds the antigen, greatly differs from one antibody to the next

constant

this part of the antibody is responsible for effector functions, does not differ from one antibody to the next

heavy chain, IgM, IgG, IgA, IgD, IgE

orange (name and types)

light chain, kappa, lambda

blue (name and types)

IgA dimer, IgM pentamer

two classes of antibodies that can glutonate using J chains

all types of biomolecules (proteins, carbs, lipids, nucleic acids)

antibodies can bind epitopes from

Igalpha and IgBeta

BCR requires these signaling protiens and a membrane-bound antibody to allow signaling for robust proliferation (secretion of the same class of antibody with the same antigen specificity)

one unique

each b cell has ____ BCR(s) that recognize(s) an antigen epitope EXCEPT during development

alternative splicing and recombination before transcription

how we get diversity from only 25k genes

D

segment spliced in the variable region for the heavy chain (in front of the constant region)

VJ

segment spliced in the variable region for the light chain (in front of the constant region)

TdT (deoxynucleotidyl transferase)

cut off loop in Ig gene arrangement, add random nucleotides to the gene (DNA) to increase diversity in antigen specificity (variable region)

RAG 1 and 2

create loop between genes during somatic recombination of DNA

IgM and IgD

Ig gene arrangements that are expressed together on one B cell, since no switch region exists between them, difference between them determined by RNA splicing (NOT DNA)

RNA splicing

determines IgM/IgD (constant region)(determined by polyadenylation), and if membrane-bound or secreted (include hydrophobic region or not)

DNA splicing

determines variable region (VDJ) (same within the same B cell)

B cell activation

not made in response to pathogen, select specific cell that proliferates creating an army of cells that can respond

internalize pathogens and present to T cells and secrete antibodies that flag pathogens for destruction

B cell immunity

T-independent type 2 antigens (TI-2)

have repeating epitopes, allowing cross-linkage of several BCRs to stimulate activation

T-independent type 1 antigens/mitogens

bind PRRs (similar to TLRs) in addition to the BCR to stimulate activation

T-dependent antigen (TD)

activation signals provided by T cells